1. Field of the Invention
The present invention relates to an end face polishing apparatus for polishing an end face of a rod-shaped member such as a fiber for optical communication.
2. Description of the Background Art
Fibers for optical communication are adhesively secured in the central hole of a ferrule, a main member of a connector, and then the ferrule end face and the end face of fibers are polished together and thus finished into a smooth, mirror surface. If the polished end faces of the ferrule and the fibers are not vertical to the central axis of the ferrule or if there is a flaw on the polished faces, the precision in positioning such ferrules as they are connected facing each other in an optical connector is lowered, and the loss increases. Therefore, the face of the ferrule including the optical fibers must be polished with high precision.
A conventional apparatus for polishing the end faces of optical fibers is disclosed for example by Japanese Patent Laid-Open No. 26456/1991. The disclosed end face polishing apparatus includes an eccentric adapter that rotates on a circle concentric with a rotating disc, and a planetary gear that transmits the rotation of a revolving motor to the eccentric adapter. These elements are coupled in a lapping machine, so that the lapping machine is allowed to rotate and revolve, while the end faces of a plurality of ferrules held by a polishing fixture are pressed against a lapping member secured to the lapping machine for lapping.
As described above, in the conventional optical fiber end face polishing apparatus, the plurality of ferrules held by the polishing fixture are pressed by a spring or the like against the lapping member secured to the lapping machine that rotates and revolves. However, the ferrules are polished based on time, and the polishing length for the ferrules cannot be controlled. When the ferrules mounted on the polishing fixture have the same length, there would be no problems. However their lengths are not equal because of the precision of ferrules or adhesive used to secure optical fibers coming out from the tip ends of ferrules and cured. When therefore such ferrules having different lengths are slid into contact with the lapping machine, the polishing fixture could be inclined relative to the lapping machine, and the lapping angle, the radius of curvature and the eccentricity could be deviated. The ferrules after the polishing could have different lengths.
The present invention overcomes the disadvantages of the conventional art and it is an object of the invention to provide an end face polishing apparatus with improved polishing precision regardless of the length of ferrules when end faces of the ferrules are polished.
According to a first aspect of the present invention directed to a solution to the above disadvantages, an end face polishing apparatus polishing a rod-shaped member mounted at a polishing fixture by pressing the rod-shaped member against a lapping member on a lapping machine provided on a surface plate which is supported at the main body of the apparatus to rotate and rock includes a plurality of rod-shaped guide members provided at the polishing fixture and radially outwardly projecting, and a tubular member capable of supporting the polishing fixture through the guide members on the surface plate. The guide members at the polishing fixture and the tubular member abut against each other, so that the movement of the polishing fixture in the pressing direction is restricted.
According to a second aspect of the invention, in the end face polishing apparatus according to the first aspect, the polishing fixture is provided with at least three such guide members.
According to a third aspect of the invention, in the end face polishing apparatus according to the second aspect, the polishing fixture is provided with six such guide members.
According to a fourth aspect of the invention, in the end face polishing apparatus according to any one of the first to third aspects, the tubular member is placed on the surface plate as its movement in the radial and circumferential directions is restricted.
According to a fifth aspect of the invention, in the end face polishing apparatus according to the fourth aspect, the tubular member and the surface plate are closely contacted by magnetic force.
According to a sixth aspect of the invention, in the end face polishing apparatus according to any one of the first to fifth aspects, the rod-shaped member is a ferrule including a ferrule tubular body for holding optical fibers and a collar member provided at a rear end of the ferrule tubular body for holding coated optical fibers.
According to a seventh aspect of the invention, in the end face polishing apparatus according to any one of the first to six aspects, the position to provide the lapping machine at the surface plate and the position to provide the tubular member are level and controlled in height by grinding, and the heights of the lapping machine and the tubular member are controlled by grinding.
According to an eighth aspect of the invention, an end face polishing apparatus polishes a rod-shaped member mounted at a polishing fixture by pressing the rod-shaped member against a lapping member on a lapping machine provided on a surface plate that is supported at the main body of the apparatus to rotate and rock, the polishing fixture has a plurality of rod-shaped guide members radially outwardly projecting, and the apparatus includes a tubular member supporting the polishing fixture through the guide members on the surface plate.
According to a ninth aspect of the invention, the surface of the guide member in abutment against the tubular member in the end face polishing apparatus according to the eighth aspect is a plane.
According to a tenth aspect of the invention, the surface of the tubular member in abutment against the guide member in the end face polishing apparatus according to the eighth aspect is a plane.
According to an eleventh aspect of the invention, the plane in the end face polishing apparatus according to the eighth aspect is horizontal.
According to a twelfth aspect of the invention, an end face polishing apparatus includes a tubular member at the outer periphery of a surface of a surface plate, and a lapping machine provided on the surface of the surface plate, and the lapping machine is parted from the tubular member in the axial direction and has a height lower than that of the tubular member.
According to a thirteenth aspect of the invention, an end face polishing apparatus includes a tubular member at the outer periphery of a surface of a surface plate, a lapping machine that is provided on the surface of the surface plate, parted from the tubular member in the axial direction and has a height lower than that of the tubular member, and a polishing fixture having a guide member held slidably at a surface on the side of the tubular member opposite to the side facing the surface plate.
According to a fourteenth aspect of the invention, an end face polishing apparatus includes a tubular member at the outer periphery of a surface of a surface plate, a lapping machine that is provided on the surface of the surface plate, parted from the tubular member in the axial direction and has a height lower than that of the tubular member, and a polishing fixture having a guide member thereon. The guide member is held slidably at a surface on the side of the tubular member opposite to the side facing the surface plate.
According to a fifteenth aspect of the invention, an end face polishing apparatus includes a tubular member at the outer periphery of a surface of a surface plate, and a lapping machine parted from the tubular member in the axial direction and having a height lower than that of the tubular member on the surface of the surface plate, and the polishing height is controlled based on the difference between the heights of the tubular member and the lapping machine.
According to a sixteenth aspect of the invention, an end face polishing jig includes a plurality of guide members radially outwardly projecting.
According to a seventeenth aspect of the invention, a polishing fixture holds a ferrule at an inclined surface on a outer peripheral side thereof, the ferrule includes a ferrule tubular body for holding optical fibers and a collar member provided at the rear end of the ferrule tubular body for holding coated optical fibers, the polishing fixture holds the ferrule so that the front end of the ferrule tubular body is positioned at the lower side and the lower part of the circle of the collar member in contact with the outer periphery of the ferrule is positioned at the upper surface.
According to an eighteenth aspect of the invention, an end face polishing jig includes a guide member radially outwardly projecting at the upper surface of the polishing fixture in the seventeenth aspect, and having a lower surface in a position on an extension of the upper surface of the polishing fixture.
According to the invention, a polishing fixture is provided with a guide member and a tubular member capable of supporting the polishing fixture through the guide member on a surface plate, so that the polishing fixture can be kept parallel to the surface plate, and the polishing precision for bar-shaped members can be improved. In addition, the lengths of the bar-shaped members after polishing can be equalized.